1S 3.7V 3A Li-ion BMS PCM Battery Protection Board

1S 3.7V 3A Li-ion BMS PCM Battery Protection Board is an essential component that provides critical safety management for single-cell (1S) Lithium-ion or Lithium-Polymer battery packs. This specialized Battery Protection Circuit Module (PCM), often referred to as a BMS, actively monitors the battery’s voltage and current, immediately shutting down the circuit if it detects overcharge, over-discharge, or short-circuit conditions. Consequently, this small board significantly prolongs the battery’s lifespan and prevents catastrophic failure, like swelling or fire, ensuring the safety and reliability of your portable electronic devices. Furthermore, its low continuous discharge current rating of 3A makes it perfectly suited for low-power devices, where size and high safety standards are paramount.

Key Features:

• Comprehensive Protection: The board offers three core protections: overcharge detection, over-discharge detection, and short-circuit protection, safeguarding the single Li-ion cell effectively.
• Low Current Design: Rated for a maximum continuous discharge current of 3A, it targets portable, low-power applications like small electronic tools and battery backups.
• Integrated MOSFETs: Uses high-quality power MOSFETs to manage the charge and discharge paths, ensuring quick and reliable switching when protection thresholds are exceeded.
• Low Standby Consumption: The quiescent current draw is minimal, therefore maximizing the battery’s shelf life and minimizing power wastage during periods of inactivity.
• Compact Form Factor: Features an extremely small, lightweight PCB design, allowing easy integration into space-constrained enclosures.

Technical Specifications:

• Battery Cell Series (S): 1S (Single Cell)
• Nominal Battery Voltage: 3.7 V (Li-ion/Li-Polymer)
• Max Continuous Discharge Current (I_D): 3 A
• Overcharge Detection Voltage (V_OC): Typically 4.25 ± 0.05 V
• Over-discharge Detection Voltage (V_OD): Typically 2.4 ± 0.1 V
• Short-Circuit Protection: Yes, immediate shutdown and auto-recovery upon load removal.
• Internal Resistance (R_DS(ON)): ≤ 60 mΩ (Ensures low power loss during operation)

Mechanical Specifications:

• Component Type: Surface Mount Technology (SMT) on a rigid PCB
• Mounting: Solder pads for wiring connections; designed for embedding within battery packs.
• Operating Temperature Range: −40°C to +85°C

Dimensions:

• Length: ≈ 17.5 mm
• Width: ≈ 17.5 mm
• Thickness (PCB only): ≈ 1.0 mm
• Weight: ≈ 0.8 g (Extremely light for portable use)

Pinout and Wiring:

• B+: Connect directly to the positive terminal of the single Li-ion/Li-Polymer cell.
• B−: Connect directly to the negative terminal of the single Li-ion/Li-Polymer cell.
• P+: This is the protected output and charging positive terminal (connect to the load/charger positive).
• P−: This is the protected output and charging negative terminal (connect to the load/charger negative).
• Wiring Note: Always connect the B- side first, and subsequently connect the P- side to the charger/load. Ensure short, heavy gauge wires for high current paths.

Datasheet Reference:

• Download HX-1S-A1 Protection Board (Generic 1S 3A BMS) Datasheet Reference

Commonly Used in:

• Wearable Electronics: Protecting batteries in smartwatches, fitness trackers, and hearing aids.
• Power Banks: Managing the single cell within small, custom-built portable chargers.
• RC Hobbies: Providing safety for 1S LiPo batteries used in small drones and micro RC vehicles.
• Small Tools: Integrated into low-power devices like laser pointers, small LED flashlights, and portable meters.

Applications:

• Circuit Protection: Preventing dangerous conditions like thermal runaway caused by charging imbalances or shorts.
• Battery Management: Optimizing the charging process and ensuring the cell operates within its Safe Operating Area (SOA).
• DIY Projects: Essential for hobbyists building custom battery packs for various electronics projects.

Equivalent Models:

• DW01A + 8205A: Generally, most 1S protection boards use this common integrated circuit pairing (Controller + Dual MOSFET), making them functionally equivalent.
• HX-1S-A1: A popular generic model widely used in the market that matches these specifications.
• Seiko Instruments S-8261 Series: Higher-end controllers that provide similar 1S protection features.

Package Includes:

• 1 x 1S 3.7V 3A Li-ion BMS PCM Battery Protection Board